Abstract:
Due to increase in the use of bisphenol A (BPA) for the manufacture of polycarbonate plastics and its release into the environment, it becomes crucial to investigate its effect on soil health and growth of plants especially food crops. This research was carried out on soils polluted with different concentration of BPA and remediated with consortium of selected actinobacteria. Okra and tomato were cultivated and grown on the polluted and remediated soils over a 90-day experimental period. In this study, bisphenol A was applied at varying concentrations. Activities of six soil enzymes (acidic phosphatase, catalase, alkaline phosphatase, β-Glucosidase, dehydrogenases, urease) were monitored at 14 day intervals. Growth parameters (height, girth and number of leaves) of the plants were also monitored. Activities of enzymes in the bioremediated pots were compared with their respective controls. Results revealed that enzymes under study showed gradual increase in activities between 15 day and 45 day.
A decline in activities was observed above 60 day. Highest activity for β-glucosidase, dehydrogenase, urease, and acid phosphatase in both polluted and bioremediated soils were recorded on 45 day while catalase and alkaline phosphatase showed highest activity at 30 day. However, highest β-glucosidase (58 and 64 % for okra and tomato respectively), dehydrogenase (119 and 173 % for okro and tomato respectively), urease (129 and 66 % for okra and tomato respectively), acid phopshatase (254 and 87 % for okra and tomato respectively), catalase (95 and 150 % for okra and tomato respectively) and alkaline phosphatase (221 and 220 % for okra and tomato respectively) activities for the test (bioremediated soils) were observed in the pots contaminated with 125 mg of bisphenol A.
Results from the enzyme assays studies coupled with GC-MS analysis of BPA metabolites clearly revealed the effectiveness of the consortium of microorganisms at degrading BPA.
